The theory of relativity predicts that if you accelerate a material object toward the speed of light, three things occur: the length of the object appears to decrease toward zero, the mass appears to increase toward infinity, and time appears to slow to a stop. Thus to accelerate a material object to the velocity of light, it would take an infinite amount of energy to do so.
The chart above shows a plot of the Lorentz-Einstein transformation based on percentages. The plot consists of a perfect quarter-circle, equivalent to a simple Pythagorean factor derived from trigonometry. As you can see from the chart, if an object travels at 87% of the speed of light, the length in the direction of travel of the object would appear (from an outside observer) to have diminished by 50 percent. At light speed the length of the object would disappear and the mass would appear infinite, and time would halt to a stop.
In spite of the extreme mass densities predicted for large black holes, they would have a finite amount of mass. And because no one has ever detected an infinite mass in the universe (because if they existed they would probably have crushed us by now) it probably means the impossibility of ever achieving light speed, either from nature or intelligent design.